Cytogenetic abnormalities predict survival after allogeneic hematopoietic stem cell transplantation for pediatric acute myeloid leukemia: a PDWP/EBMT study.

Poor-risk (PR) cytogenetic/molecular abnormalities generally direct pediatric patients with acute myeloid leukemia (AML) to allogeneic hematopoietic stem cell transplant (HSCT). We assessed the predictive value of cytogenetic risk classification at diagnosis with respect to post-HSCT outcomes in pediatric patients. Patients younger than 18 years at the time of their first allogeneic HSCT for AML in CR1 between 2005 and 2022 who were reported to the European Society for Blood and Marrow Transplantation registry were subgrouped into four categories. Of the 845 pediatric patients included in this study, 36% had an 11q23 abnormality, 24% had monosomy 7/del7q or monosomy 5/del5q, 24% had a complex or monosomal karyotype, and 16% had other PR cytogenetic abnormalities. In a multivariable model, 11q23 (hazard ratio [HR] = 0.66, P = 0.03) and other PR cytogenetic abnormalities (HR = 0.55, P = 0.02) were associated with significantly better overall survival when compared with monosomy 7/del7q or monosomy 5/del5q. Patients with other PR cytogenetic abnormalities had a lower risk of disease relapse after HSCT (HR = 0.49, P = 0.01) and, hence, better leukemia-free survival (HR = 0.55, P = 0.01). Therefore, we conclude that PR cytogenetic abnormalities at diagnosis predict overall survival after HSCT for AML in pediatric patients.

Risk factors for a severe disease course in children with SARS-COV-2 infection following hematopoietic cell transplantation in the pre-Omicron period: a prospective multinational Infectious Disease Working Party from the European Society for Blood and Marrow Transplantation group (EBMT) and the Spanish Group of Hematopoietic Stem Cell Transplantation (GETH) study.

Risk factors for severe SARS-Cov-2 infection course are poorly described in children following hematopoietic cell transplantation (HCT). In this international study, we analyzed factors associated with a severe course (intensive care unit (ICU) admission and/or mortality) in post-HCT children. Eighty-nine children (58% male; median age 9 years (min-max 1-18)) who received an allogeneic (85; 96%) or an autologous (4; 4%) HCT were reported from 28 centers (18 countries). Median time from HCT to SARS-Cov-2 infection was 7 months (min-max 0-181). The most common clinical manifestations included fever (37; 42%) and cough (26; 29%); 37 (42%) were asymptomatic. Nine (10%) children following allo-HCT required ICU care. Seven children (8%) following allo-HCT, died at a median of 22 days after SARS-Cov-2 diagnosis. In a univariate analysis, the probability of a severe disease course was higher in allo-HCT children with chronic GVHD, non-malignant disease, immune suppressive treatment (specifically, mycophenolate), moderate immunodeficiency score, low Lansky score, fever, cough, coinfection, pulmonary radiological findings, and high C-reactive protein. In conclusion, SARS-Cov-2 infection in children following HCT was frequently asymptomatic. Despite this, 10% needed ICU admission and 8% died in our cohort. Certain HCT, underlying disease, and SARS-Cov-2 related factors were associated with a severe disease course.

T-cell replete cord transplants give superior outcomes in high-risk and relapsed/refractory pediatric myeloid malignancy.

Stem cell transplant (SCT) outcomes in high-risk and relapsed/refractory (R/R) pediatric acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) have been historically poor. Cord blood (CB) allows T-cell replete CB transplant (TRCB), enabling enhanced graft-versus-leukemia. We consecutively collected data from 367 patients undergoing TRCB (112 patients) or other cell source (255 patients) SCT for pediatric AML/MDS in the United Kingdom and Ireland between January 2014 and December 2021. Data were collected about the patient's demographics, disease, and its treatment; including previous transplant, measurable residual disease (MRD) status at transplant, human leukocyte antigen-match, relapse, death, graft versus host disease (GvHD), and transplant-related mortality (TRM). Univariable and multivariable analyses were undertaken. There was a higher incidence of poor prognosis features in the TRCB cohort: 51.4% patients were MRD positive at transplant, 46.4% had refractory disease, and 21.4% had relapsed after a previous SCT, compared with 26.1%, 8.6%, and 5.1%, respectively, in the comparator group. Event free survival was 64.1% within the TRCB cohort, 50% in MRD-positive patients, and 79% in MRD-negative patients. To allow for the imbalance in baseline characteristics, a multivariable analysis was performed where the TRCB cohort had significantly improved event free survival, time to relapse, and reduced chronic GvHD, with some evidence of improved overall survival. The effect appeared similar regardless of the MRD status. CB transplant without serotherapy may be the optimal transplant option for children with myeloid malignancy.

Complications and Utility of Gastrointestinal Endoscopy Post Hematopoietic Stem Cell Transplantation: An 11 Year Experience.

OBJECTIVES: Diagnostic gastrointestinal (GI) endoscopy is used to differentiate GI graft versus host disease (GI-GvHD), which requires escalation of immunosuppressive treatment (IST), from other conditions such as viral infection, which may require reduction of IST. The aim of this study was to establish the clinical utility of GI endoscopy post hematopoietic stem cell transplant (HSCT) and the complication rate of these procedures. METHODS: This was a single-center observational retrospective cohort study. Hospital pediatric endoscopy and HSCT databases identified patients between January 2010 and December 2020. GI-GvHD was diagnosed if there were positive histological findings and clinical context. Data collected included demographics, timing of endoscopy post-HSCT, clinical utility, and complications of endoscopy. The endoscopy was deemed to be "clinically useful" if it resulted in a change of clinical management or helped to narrow down the differential diagnosis for the clinical team. RESULTS: Three hundred thirty-nine HSCT occurred in 320 children during the study period. Sixty-six of 339 (19%) HSCT needed an "endoscopy episode." One hundred nineteen endoscopies were performed (53 concurrent upper and lower GI endoscopies, 11 upper GI endoscopies, and 2 lower GI endoscopies). Four of 119 (3%) endoscopies had complications: septic shock (1), duodenal hematoma (1), GI bleeding (1), and colonic perforation (1). Four patients had incomplete records to assess utility of endoscopy. Fifty-seven of 62 (92%) endoscopy episodes were "clinically useful," and 41 of 62 (66%) had a change in IST. CONCLUSIONS: The clinical utility of endoscopy is high and in the majority of cases is associated with a change in patient management. Children post-HSCT are at high risk of complications from endoscopy; this should be made clear in the process of obtaining consent for procedures.

Genome-edited, donor-derived allogeneic anti-CD19 chimeric antigen receptor T cells in paediatric and adult B-cell acute lymphoblastic leukaemia: results of two phase 1 studies.

BACKGROUND: Genome-edited donor-derived allogeneic anti-CD19 chimeric antigen receptor (CAR) T cells offer a novel form of CAR-T-cell product that is available for immediate clinical use, thereby broadening access and applicability. UCART19 is one such product investigated in children and adults with relapsed or refractory B-cell acute lymphoblastic leukaemia. Two multicentre phase 1 studies aimed to investigate the feasibility, safety, and antileukaemic activity of UCART19 in children and adults with relapsed or refractory B-cell acute lymphoblastic leukaemia. METHODS: We enrolled paediatric or adult patients in two ongoing, multicentre, phase 1 clinical trials to evaluate the safety and antileukaemic activity of UCART19. All patients underwent lymphodepletion with fludarabine and cyclophosphamide with or without alemtuzumab, then children received UCART19 at 1·1-2·3 × 106 cells per kg and adults received UCART19 doses of 6 × 106 cells, 6-8 × 107 cells, or 1·8-2·4 × 108 cells in a dose-escalation study. The primary outcome measure was adverse events in the period between first infusion and data cutoff. These studies were registered at ClinicalTrials.gov, NCT02808442 and NCT02746952. FINDINGS: Between June 3, 2016, and Oct 23, 2018, seven children and 14 adults were enrolled in the two studies and received UCART19. Cytokine release syndrome was the most common adverse event and was observed in 19 patients (91%); three (14%) had grade 3-4 cytokine release syndrome. Other adverse events were grade 1 or 2 neurotoxicity in eight patients (38%), grade 1 acute skin graft-versus-host disease in two patients (10%), and grade 4 prolonged cytopenia in six patients (32%). Two treatment-related deaths occurred; one caused by neutropenic sepsis in a patient with concurrent cytokine release syndrome and one from pulmonary haemorrhage in a patient with persistent cytopenia. 14 (67%) of 21 patients had a complete response or complete response with incomplete haematological recovery 28 days after infusion. Patients not receiving alemtuzumab (n=4) showed no UCART19 expansion or antileukaemic activity. The median duration of response was 4·1 months with ten (71%) of 14 responders proceeding to a subsequent allogeneic stem-cell transplant. Progression-free survival at 6 months was 27%, and overall survival was 55%. INTERPRETATION: These two studies show, for the first time, the feasibility of using allogeneic, genome-edited CAR T cells to treat patients with aggressive leukaemia. UCART19 exhibited in-vivo expansion and antileukaemic activity with a manageable safety profile in heavily pretreated paediatric and adult patients with relapsed or refractory B-cell acute lymphoblastic leukaemia. The results this study are an encouraging step forward for the field of allogeneic CAR T cells, and UCART19 offers the opportunity to treat patients with rapidly progressive disease and where autologous CAR-T-cell therapy is unavailable. FUNDING: Servier.